Title: United States Virgin Islands animal fact sheets
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Permanent Link: http://ufdc.ufl.edu/UF00093446/00001
 Material Information
Title: United States Virgin Islands animal fact sheets
Physical Description: Book
Language: English
Creator: Division of Fish and Wildlife, Department of Planning and Natural Resources, United States Virgin Islands
Publisher: Division of Fish and Wildlife, Department of Planning and Natural Resources, United States Virgin Islands
Place of Publication: St. Thomas, VI
 Record Information
Bibliographic ID: UF00093446
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.

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Department of Planning and Natural Resources
Division of Fish and Wildlife
U.S.V.I. Animal Fact Sheet #01

Green Sea Turtle
Chelonia mydas


Taxonomy
Kingdom
Phylum
Subphylum -
Class
Order -
Family -
Genus -
species -


Animalia
Chordata
Vertebrata
Reptilia
Chelonii
Cheloniadae
Chelonia
mydas


Identification Characteristics
+ Prefrontal scales 1 pair
* Claws on foreflipper 1 (large in males)
* Costal scutes 4 Pairs
* Carapace smooth, rounded
* Gait (on land) parallel
+ Lower jaw edge coarsely dentate
+ Upper jaw distinct vertical rib


Description
The green sea turtle (Chelonia mydas) is a medium to
large sized sea turtle. Nesting females average 3 feet) curved
carapace (shell) length and can weigh over 400 pounds.
Hatchlings are small, with an average carapace length of 2
inches and a weight of less than 1 ounce. The carapace of
adult green turtles is smooth along lateral and posterior
margins (edges) with non-overlapping scutes (scales).
Hatchlings and juveniles have rounded carapaces.
Coloration of green sea turtles is variable, ranging from
green to gray to brown, and carapaces are frequently marked
by darker spots or streaks [Their name derives from the color
of their green fat tissues not from external coloration]. The
bottom of the carapace (plastron) is usually white or yellow.

Distribution & Habitat
Green sea turtles are circumglobal, occurring in most
tropical and sub-tropical waters of the world. In the eastern
US, they are found from Texas to Massachusetts, and
throughout the U.S. Caribbean.
Green sea turtles have a life history similar to most other
sea turtles adults and juveniles occur in different habitats.
Hatchlings and juveniles are found offshore whereas adults
occur in coastal waters. Although little is known of their
behavior during the first years of life, they are common in
sargassum driftlines (oceanic convergence zones). Their
strong counter-coloration pattern and their behavior in
laboratory experiments also suggest that juvenile green sea


turtles may forage in open waters (unlike hawksbill and
loggerhead turtles).
Juvenile green sea turtles eventually recruit to coastal
habitats at around 1 foot (+ 4 inches) carapace length (a
significantly smaller size than other sea turtle species).
Juveniles show very high site fidelity to their feeding areas.
They remain in coastal habitats throughout adulthood. Adult
green sea turtles continue to forage in seagrass beds and algal
plains, although they may establish permanent sleeping
shelters among nearby rocks or on coral reefs.

Diet
The diet of most marine turtles is still poorly understood.
The pelagic (living in the open ocean) hatchlings and juveniles
are believed to forage as opportunistic carnivores, feeding
upon jellyfish, small mollusks, and crustaceans. When
juveniles recruit to coastal environments, they shift to an
herbivorous diet comprised of seagrasses and algae. They
remain herbivores throughout adulthood, although they may
ingest gelatinous organisms such as jellyfish or egg cases.
Growth rates of green sea turtles are difficult to
determine. Juveniles and young adults (1 to 2 foot carapace
length) are thought to grow at about 2 inches/yr. Older turtles
seem to grow at a slower rate, and hatchlings grow faster.







Reproduction
Similar to other sea turtles, female green sea turtles
emerge from the ocean to lay their eggs. In the Virgin Islands,
green sea turtles may nest at any time of the year, however the
peak nesting season is from August to October. Nesting
almost always takes place at night. Females emerge and crawl
up the beach (sometimes covering a considerable distance) to
dig their nests at the edge of the open beach, usually near
vegetation.
Nest preparation is an elaborate and time-consuming
effort. Females first sweep the loose dry sand away from a
nest site a process called "body pitting." The female then
uses her rear flippers to dig a hole by alternately scooping
sand with left and right flippers, flinging loose sand forward
over her head. Nest depth is determined by the length of the
rear flippers. When the flippers can't reach the bottom, the
hole is deep enough. She then proceeds to lay approximately
110 eggs in the hole. The number of eggs laid is directly
related to body size, and a large female may lay as many as
200 eggs in one nest. After laying, females disguise their
nests by spreading sand over the area.
Female green sea turtles will lay between 1 and 7 clutches
of eggs each year. These nests can be spread out on our
beaches or on the beaches of neighboring islands. Nesting
activities are repeated approximately every 14 days, with an
average of 4.5 successful nests per year. Only about half of
green sea turtle nesting attempts are successful (eggs are laid)
and unsuccessful nests are simply abandoned. This is why one
can see numerous body pits on the upper beaches.
The incubation period for green sea turtle eggs averages
55-60 days, after which hatchlings emerge at night from the
nest and scramble towards the ocean. Hatchlings need to avoid
terrestrial predators by crawling straight to the water. They
have evolved a unique way of determining where the sea is
located. The hatchlings look for an area on the horizon that is
bright. This makes sense for turtles, vegetation creates very
dark shadows inland and the combination of starlight and
reflections of starlight on the ocean make it much brighter. So
the hatchlings crawl toward these brighter areas and into the
ocean. Today many people use inappropriate lights near
nesting beaches and hatchlings end up crawling toward the
beach lights, were many are run over by cars, eaten by dogs,
cats and other exotic animals.

Conservation
The green sea turtle is listed by the U.S. Fish and Wildlife
Service as a threatened species throughout the Caribbean.
CITES (Convention on International Trade of Endangered
Species) has listed the green sea turtle under Appendix I -
among the most endangered of the CITES-listed animals and
plants. All sea turtles are protected by territorial law, which
prohibits the harvesting of adults and eggs. Unfortunately,
existing regulations have not eliminated poaching of green sea
turtles. In the Virgin Islands, this species is the most
frequently poached sea turtle.
All sea turtles are susceptible to injury from boats and
propellers. They are air breathing reptiles, which means they
must come to the waters surface to breath. It is important for
boat drivers to realize that they need to be looking for Turtles
and other basking animals as well as swimmers while boating
in near shore waters.


Sea turtles can ingest or become tangled in fishing line,
nets or other marine debris. This can lead to amputation of
tangled limbs, digestive problems, and frequently to death.
Green sea turtles are also threatened by habitat
modification. Beach erosion and erosion control methods
have reduced or altered nesting habitats. Installation of
lighting in coastal areas interferes with behavioral responses
of hatchlings, thus reducing survival. These factors have also
contributed to a decline in green turtle populations.

What you can do to help
1. If you see any turtle nesting or hatching events, please
write down the date, time and location you saw the turtles
then call the Division of Fish and Wildlife at 340-772-
1955 (on St. Croix) or 340-775-6762 on St. Thomas/St.
John to report the event.
2. Hatchlings can crawl to the water themselves, if you see
hatchlings making their way into the water, please let
them complete the journey themselves.
3. Please make an extra effort to keep plastic out of the
marine environment.
4. Turtles, especially hatchlings, will head toward the
brightest light source on the beach. This used to be star
and moon light shining on the ocean, but today it may be
street or building lights. If possible turn off lights that
shine on and toward the beach, when hatchlings are
emerging.
5. Do not take flash pictures or shine lights directly toward
the turtles it will disorient them. Like us, turtle eyes will
maintain the ghost image of the flash, only the hatchlings
see this as a bright area and will crawl toward it.
6. If hatchlings emerge during the day, you may protect
them from predators, and guide them to the waters edge.
7. If you see a nesting turtle do not crowd around it and do
not harass it. You may observe nesting from a distance.
Be sure to stay behind the front flippers of the turtle so
that you do not disturb her. No flash photography.
8. Occasionally turtles will nest during the day. If you see a
daytime nesting sea turtle, please call the Division of Fish
and Wildlife immediately.
9. For more information on this and other animals in the
Virgin Islands please visit our web site at:
www.vifishandwildlife.com


PRODUCED IN 2002 by W. Coles, W. Toller
THIS PUBLICATION WAS PRODUCED WITH FUNDS
FROM THE WILDLIFE CONSERVATION AND
RESTORATION PROGRAM (WCRP).
FOR MORE INFORMATION ON
OUR NATIVE ANIMALS CONTACT

DIVISION OF FISH AND WILDLIFE

6291 ESTATE NAZARETH, 101,
ST. THOMAS, VI 00802
PHONE 340-775-6762 FAX 340-775-3972
or
45 MARS HILL, ST. CROIX, VI 00840
PHONE 340-772-1955 FAX 340-772-3227




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